Expanding pulley



s. aunaass. EXPANDING PULLEY.

APPLICATION FILED NOV. 19, I919. RENEWED JAN. 24, I921- Patented Aug. 23, 1921.

11, ef g z red 4 UNITED E enonen sn'rrnnss, or LQS ANGELES, CALIFORNIA.

i EXPANDING rnLLnY.

Specification of Letters Iatent. I Patented Aug, 23 1921 Application filed' November 19, 1919, Serial No. 339,187. Renewed January 24, 1921. Serial No. 439,690.

I To all whom it may, concern: 7

Be, it known that'I, Gnonen BUTTRESS, a

citizen of the UnitedStates, residing at Los Angeles, county of'Los Angeles, .and State of California, have invented a certain'new and useful Improvement in Expanding Pulleys, of whichthe following is a specification.

My inventionrelates to an improvement in pulleys, and has particular referenceto pulleys of the. expanding. type for varying the velocity ratio by expansion and corn traction of the periphery, one of the objects of this invention being to provide a simple, light and efficient unit, of economical construction, in which, during all conditions ofexpansion and contraction, a smooth and continuous peripheral face may be had whereby to afford a continuous friction hold for the belt or other. driving or driven medium.

Other objects will appear fromthe sub-- joined specification in connection with the accompanying drawing, which illustrates a preferred form of embodiment of the in vention, and in which,

Figure l is a vertical section, taken on line l1, Fig. 2.

Fig. 2 is a side view, partly in section showing a fragment of one of the plates for holding rigid the radial arm of the pulley.

Fig. 3 is an enlarged front view of onev of the arcuate sections showing the anchoring thereto of the facing strip or ribbon and the continuation of the strip under the fastened or anchored end thereof.

Fig. 4 is a horizontal sectional view taken on line 4-4, Fig. 2, of one of the arcuate sections composing the pulley, and

Fig. 5 is a plan view showing means for expanding and contracting the pulley, and means tending to convert the pulley to its largest diameter or size.

The invention comprises a series of flanged arcuate sections or segments 1, each provided with ears or lugs 2, for pivotally connecting the ends 8 of radial, arms 3, the opposite ends of which are pivotally attached to ears 5, on disks 6, secured to drums tion 10, rotund on the underside, and spaced.

from the surface of the arcuate section to form a groove "11, for the accommodation joints.

of a circumferential band 12, preferably of resilient material, which entirely encircles equal to the thickness thereof, is held spaced from the surface ofthe arcuate section 1 111 order to afford space for the returning convolution 12 of the band 12, which convolution continues for a distance desired and governable by the extent of expansion of the pulley, and terminates within the area of the associated arcuate sections. The

movement'of the drums 7 on the shaft8, is effected by any suitable mechanism, as

toggle joints 14, the toggles 15 of which are pivotally connected to straps 16' of drums 17, pinned on thesha'ft, and levers 18 being pivotally attached to the junction of the permanently attached.

Obviously, when two such pulleys are connected by a belt, the expansion of one and the contraction of the other, may be effected simultaneously by the operation of the bar 19, which, after the adjustment is made, may be held rigid by any means.

In order to offset the strain on the arms 3, during the operation of varying the pulley periphery, two disks 20 and 21 may be provided. These disks or circular plates are securely held together by any means, as'bolts 24, and are provided with slots 22 and 23, into which the ends of the radial arms 3 extend and in which they may move during the expansive andv contractive movements of the arcuate sections.

In order to make easy the expansion of the arcuate members or sections during rotation of the same, the disks 6 of the drums 7 may be interconnected by a means tend-' ing to draw the drums toward each other,

and such means may comprise springs 25, which, as is obvious, reduce the power required for expanding the pulley and likewise resist the normal tendency of the pulley to contract by reason of the pressure of the belt.

Each of the arcuate sections 1 is prefer'-' ably provided with an antifriction means for the band 12 during the movement thereof. and such antifri'ctlonfmeans may be rollers 26, or any other means suitable for the purpose.

hat I claim, is 1 l. A pulley comprising in combination a series'ofarcuate sections constructed togr-ip a band againstradial movement in respect thereto and to permit the band to slide cir- .cumferentially, a series of'drums, radial arms connecting said drums and sections,-a' convolution of a resilient band fastened at on end to one of said sections and encircling the others of said sectionsso as to slide circumferentially in the latter, said bandbeing free at the other end and continuing under said sections.

:2; A pulley comprising in combination with a shaft, a pair of carriers secured to said shaft, a. series of arcuate sections mounted to radially slide in said carriers,

said sections being constructed to grip a band against-radial movement with respect thereto and to permit the band to slide circumferentially, a series of drums, radial arms connecting said drums and sections, a convolution of a-resilient band fastened at one-end to one of said sections and encircling the others ofv said sections so as to slide circumferentially in the latter, said bandibeing free at the other endand continuing under said sections.

3. A pulley comprising in combination a with a shaft, carrier disks securedto said shaft and having. radial: guide ways; a series of arcuate sections slidably mounted in said guide ways, said sections being constructed to grip a hand against radial movement with respect thereto and to permit the band to slide 'circumferentially', a series of drums, radial arms connecting said drums and: sections, a convolution of a resilient band fastened at one end toone of sa1d'sections and encircling others of said sections so as-to slide circumferentially in the latter, said band being free at the other end and continuing under said sections.

4;. A pulley comprising in combination a series of arcuatesections constructedto grip a hand against radial movement with respect thereto and topermit theband to slide circumferentially, a series of drums, radial arms connecting said drums and: sections, a

CODVOlIltlOIL of a resllient band fastened at i one end tol one of said. sections and encircling the others of said. sections so as to 

